Z axis moves backwards?

[zaebis]

Just tinckering with my new CNC mill and discovered that it moves the head up when Mach 3 decrementing Z DRO and moves the head down when Z is being incremented. I wonder if there is a switch of some kind to reverse that in Mach3 or it may be inside the machine the wiring screwed upto the stepper for Z.

[stevespo]

I don't have Mach in front of me, but there is definitely a configuration setup to control motor direction. I had to do this myself when I first set things up.

From the manual, page 5-12:

"If the direction is wrong then, Save the axis and either (a) change the Low Active setting for the Dir pin of the axis in Config>Ports and Pins>Output Pins tab (and Apply it) or (b) check the appropriate box in Config>Motor Reversals for the axis that you are using. You can also, of course, just switch off and reverse one pair of physical connections to the motor from the drive electronics. "

Steve

[ger21]

The manual is several years old and outdated. The correct way to reverse it now is go to Config > Homing/Limits and check the "Reverse" column.

[stevespo]

Thanks Gerry! Those instructions didn't sound right to me, but it had been a few years since I looked at that config screen. I shouldn't assume the docs are correct. Better to double-check the actual install.

Steve

[jeremyrockjock]

Originally Posted by ger21 The manual is several years old and outdated. The correct way to reverse it now is go to Config > Homing/Limits and check the "Reverse" column.

I tried this but it does not change the motors.

[Kipper]

Originally Posted by jeremyrockjock I tried this but it does not change the motors.

It'll affect the homing direction though....hth

[ger21]

No, it doesn't. To reverse the homing direction, you check "Home Neg" > Reverse should change the direction of motor rotation. If it doesn't, something is possibly wrong with your Mach3 install.

[LeeWay]

I don't use homing on my mill. No need. It all gets cut either from part center or vise edge or stop. I change direction just swapping the direction pin high or low. No problems with it like this without homing installed. I could see how that would mess with your home directions.